1. Field of the Invention
The present invention relates to the field of signal processing.
2. Background Art
Signal processing can be difficult when the signal is a high rate signal. High rate systems may require expensive and/or custom devices for appropriate processing functionality to process the signal at the rate required. Some prior art approaches to providing devices capable of high rate signal processing are described below.
One current solution is to use commercially available microprocessors to implement the desired signal processing functionality. However, for high signal rate applications, commercial microprocessors may not be able to provide the desired signal processing rate.
Another solution is to make custom ASIC (application specific integrated circuit) devices. Such devices are designed with a specific functionality in mind. ASIC's differ from general purpose microprocessors in that they are optimized for a specific task. Even with custom devices designed for a specific function, standard techniques of circuit fabrication may still be inadequate to provide the desired signal processing rate. Using standard CMOS (complementary metal-oxide-semiconductor) techniques, ASIC's capable of an adequate signal processing rate may still be challenging to produce.
When CMOS devices (either ASIC's or mircroprocessors) are unable to provide adequate signal processing performance, another prior art solution is to implement circuits using gallium arsenide (GaAs) technology. This technology results in higher clock speeds and consequently greater signal processing rates. However, GaAs technology is expensive to design and implement and also has lower yields than silicon based CMOS technology This results in still greater costs. Another problem is that the device density of GaAs devices is lower than that of CMOS processes. This means that physically larger GaAs devices must be used, leading to greater problems with design and power management.